Cargo is typically transported in containers (“Unit Load Devices”), which are stowed in cargo holds either below the deck of passenger aircraft or below and above the deck in transport aircraft. The size and shape of Unit Load Devices vary depending upon the type of aircraft in use. Typically, and regardless of the shape or geometry of the container, one end or side of the cargo container is open for loading and unloading cargo. Various door closures have been used for opening and closing the open ends of such containers. One type of closure has been a rigid door closure which covers the opening to reduce tampering, to prevent the loss of small items, and to prevent the cargo from being exposed to dirt, moisture, and ultraviolet light. Another type of closure includes a fabric closure or curtain. In all aircraft, the gross weight of the airplane is a substantial factor, because of the cost of fuel. Even a slight reduction in weight is significant, therefore fabric doors are often preferred.
Curtain closures for air cargo containers serve several purposes. Primarily, closures keep cargo contained inside of an air cargo container and minimize the unwanted intrusion into the air cargo container. Improvements have been made in curtain closures to increase their strength using high tenacity fibers to form the curtains. These curtains have had the effect of lowering maintenance costs because the curtains having high tenacity fibers may resist damage from the rough handing common to air cargo containers. Particularly, sliding cargo within the container is unlikely to puncture the high tenacity curtains. Further, curtains made from high tenacity fibers can resist puncture from cargo handling equipment such as fork lifts.
To further increase performance and reduce wear on the curtains, curtains for air cargo containers have been coated, laminated or impregnated with materials such as ethylene vinyl acetate (EVA) to render the fabric curtains substantially waterproof and more highly resistant to oils, gasoline, and other chemicals that may be present in an airport or other shipping environment. Even still, further advances in performance can be made.